This invention relates generally to a heat exchanger assembly method and, more particularly, to an improved process for the assembly of plate fin heat exchanger coils.
A plate fin heat exchanger coil is commonly constructed with a plurality of flat, parallel plates having laterally spaced holes therein for receiving refrigerant tubes, or hair pin tubes, therein. At each end of the plate fin bundle, there is a tube sheet composed of heavier material, and adjacent the upper tube sheet, the open ends of the hair pin tubes are fluidly connected by way of `U` shaped return bends that are secured thereto by way of brazing or the like. When the coils are installed into a refrigeration system, the refrigerant is made to flow through the hair pin tubes, and the air to be cooled or heated is made to flow over the plate fins, such that a heat transfer is thereby affected.
In the assembly of plate fin heat exchangers, it is common to receive the individual plate fins from a plate fin harvester and to stack them on a rod assembly for subsequent transfer, as a bundle, to the guide rods on the lacing table. After the hair pin tubes are laced or assembled into the fin bundles, the entire assembly is then moved to a different area to facilitate the process of expanding the tubes radially outwardly to tightly engage the inner surfaces of the plate fins. It is during this transfer process that, since the holes in the plate fins are necessarily larger than the outer diameter of the hair pin tubes, the plate fins tend to slide along the tubes and may come completely off he tube. This causes not only a loss of material but also a loss of time that results from the need to replace those plate fins or, to an inferior structure in the event that they are not replaced.
It is therefore an object of the present invention to provide an improved method for assembly of plate fin heat exchangers.
Another object of the present invention is the provision in a plate fin heat exchanger assembly process for maintaining the integrity of the assembled components between the lacing and expansion processes.
Yet another object of the present invention is the provision for assembling a plate fin heat exchanger in an economical and effective manner.
The objects and other features and advantages become more readily apparent upon reference to the following descriptions when taken in conjunction with the appended drawings.